The jet stream that is going to hit Southern California is as powerful as
has ever been recorded on this planet before, over 230 mph. The jet is at
an extremely unusually low altitude, not 30,000 to 60,000 feet, but coming
as low as 8,000 feet. This jet will be traveling over the unusually warm
El Nino waters of the eastern pacific, and will be carrying freakish
amounts of energy and moisture. A huge series of storms is going to slam
into Los Angeles and the surrounding areas just one after another for day
after day for up to two weeks.

The initial storms will be very cold, with snow levels as low as 3,000
feet. Heavy rain and snow will be hitting California from San Diego to
Eureka. Next week, the driest places will see at least 3 inches of rain,
the Los Angeles basin and northern parts of the county and Ventura will
see 6 to 10 inches. The wettest areas and cells within the system will hit
with up to 20 inches of rain. Snowfall in the Sierras will be measured in
the TENS of feet. Powerful winds will be associated with this storm--like
a powerful Santa Ana but blowing in the opposite direction, west to east.
Gusts up to 80 mph are forecast.

But it gets worse. For the first time that I'm aware of, ALL of the
various models are in agreement about the second week of the storm.
Normally, beyond a week, the models diverge. But due to the extreme
strength of the weather producing factors, this time all of the models
produce the same results for the 8-14 day period.

For the week of the 24th, we will be hit with a powerful and WARM series
of storms, as strong as any we've seen. This heavy warm rainfall will fall
onto the newly laid snowpack and what will be totally saturated ground,
especially in the burn areas of LA and will produce tremendous melting and
runoff, and the potential for record flooding.

Due to the low altitude of the jet stream, 200+ mph winds will slam
directly into the Sierras, producing tornado strength winds over a 200
mile wide front. DON'T head to Mammoth for skiing when you hear about the
huge snow fall in the first week.

A friend of Scott's is a Navy weather forecaster and he told Scott that
the military is moving assets east out of the way ahead of this storm.
Planes and helicopters are migrating out of the coastal bases and into
the interior bases of Arizona and Nevada. They're taking this very
seriously.

This may sound alarmist, but websites I check related to weather modeling
are using the word "Biblical" for this system. If you can work from home
or commute by train, please plan on doing so. The LA freeway system is
going to be a mess for the next week or two.

Currently, the strong El Nino is reaching its peak in the Eastern
Pacific, and now finally appears to be exerting an influence on our
weather. The strong jet has been apparent for quite some time out over
the open water, but the persistent block had prevented it from reaching
the coast. Now that the block has dissolved completely, a
200+ kt jet is barreling towards us. Multiple large and powerful storm

systems are expected to slam into CA from the west and northwest over the
coming two weeks, all riding this extremely powerful jet stream directly
into the state. The jet will itself provide tremendous dynamic lift, in
addition to directing numerous disturbances right at the state and
supplying them with an ample oceanic moisture source. The jet will be at
quite a low latitude over much of the Pacific, so these storms will be
quite cold, at least initially. Very heavy rainfall and strong to
potentially very strong winds will impact the lower elevations beginning
late Sunday and continuing through at least the following Sunday. This
will be the case for the entire state, from (and south of) the Mexican
border all the way up to Oregon. Above 3000-4000 feet, precipitation will
be all snow, and since temperatures will be unusually cold for a
precipitation event of this magnitude, a truly prodigious amount of
snowfall is likely to occur in the mountains, possibly measured in the
tens of feet in the Sierra after it's all said and done. But there's a big
and rather threatening caveat to that (discussed below). Individual storm
events are going to be hard to time for at least few more days, since this
jet is just about as powerful as they come (on this planet, anyway).
Between this Sunday and the following Sunday, I expect categorical
statewide rainfall totals in excess of 3-4 inches. That is likely to be a
huge underestimate for most areas. Much of NorCal is likely to see 5-10
inches in the lowlands, with 10-20 inches in orographically-favored areas.
Most of SoCal will see 3-6 inches at lower elevations, with perhaps triple
that amount in favored areas.

This is where things get even more interesting, though. The models are
virtually unanimous in "reloading" the powerful jet stream and forming an
additional persistent kink 2000-3000 miles to our southwest after next
Sunday. This is a truly ominous pattern, because it implies the potential
for a strong Pineapple-type connection to develop. Indeed, the 12z GFS
now shows copious warm rains falling between days 12 and 16 across the
entire state. Normally, such as scenario out beyond day seven would be
dubious at best. Since the models are in such truly remarkable agreement,
however, and because of the extremely high potential impact of such an
event, it's worth mentioning now. Since there will be a massive volume of
freshly-fallen snow (even at relatively low elevations between 3000-5000
feet), even a moderately warm storm event would cause very serious
flooding. This situation will have to be monitored closely. Even if the
tropical connection does not develop, expected rains in the coming 7-10
days will likely be sufficient to cause flooding in and of themselves
(even in spite of dry antecedent conditions).

In addition to very heavy precipitation, powerful winds may result from
very steep pressure gradients associated with the large and deep low
pressure centers expected to begin approaching the coast by early next
week. Though it's not clear at the moment just how powerful these winds
may be, there is certainly the potential for a widespread damaging wind
event at some point, and the high Sierra peaks are likely to see gusts in
the 100-200 mph range (since the 200kt jet at 200-300 mb will essentially
run directly into the mountains at some point). The details of this will
have to be hashed out as the event(s) draw closer.

In short, the next 2-3 weeks (at least) are likely to be more active
across California than any other 2-3 week period in recent memory. The
potential exists for a dangerous flood scenario to arise at some point
during this interval, especially with the possibility of a heavy
rain-on-snow event during late week 2. In some parts of Southern
California, a whole season's worth of rain could fall over the course of
5-10 days. This is likely to be a rather memorable event. Stay tuned...

I found a virtually identical version in a Santa Monica Dispatch blog post dated 20 January 2010. However, this version attributes the first couple of paragraphs to George Wolfberg, who is president of the Santa Monica Canyon Civic Association, and the remaining paragraphs beginning with "Currently, the strong El Nino" to Professor Johnson. In addition, this version dates Professor Johnson's post as 14 January 2010. So, as commenter Bob says on that site, it sounds like he's talking about this week, not next week.

I don't know about biblical, but this is a pretty impressive storm. The waves in Ventura were reaching 17 feet on Tuesday. A piling has washed out of the pier and 5 cross-beams have broken, so that's closed. We actually had thunder!

I keep telling my Californian office-mates that this is a very respectable storm even by midwest standards!

I emailed the listed author (Samuel Y. Johnson) yesterday 1/21/2010 and his reply is below.
Have not been able to find the story in any form - nor its author - on any of the CA or Cal Fire web sites he mentions... several sites (like ones mentioned before on this thread) showed up on several Google searches... all dead ends... Found it interesting that the news outlet, Huffington.com and Daily Breeze - in NoCal? - both had it - here is Mr. Johnsons' reply:

I'm in Japan at the moment. This weather forecast did not originate with me (I'm a geologist). I received it in an email Thursday (1/14) and forwarded it on to the group I work with. I included the original source (I think it came from Cal Fire) but obviously others who in turn forwarded the message on did not so it mistakenly looks like I'm the source. I can't check the original source now because I'm working on a remote laptop. I suggest you check in with Cal Fire.

I'm in Japan at the moment. This weather forecast did not originate with me (I'm a geologist). I received it in an email Thursday (1/14) and forwarded it on to the group I work with. I included the original source (I think it came from Cal Fire) but obviously others who in turn forwarded the message on did not so it mistakenly looks like I'm the source. I can't check the original source now because I'm working on a remote laptop. I suggest you check in with Cal Fire.